1. Field of the Invention
The invention relates to a memory module structure, in particular to a module design having a high capacity up to 512 MB.
2. Description of the Related Art
As shown in FIG. 1, a conventional memory module is illustrated. The memory module is formed by arranging a plurality of dynamic random access memories 10 on a substrate 12. By the combination of the plurality of dynamic random access memories 10, the memory module may have the capacity of 64 MB, 128 MB, 256 MB or 512 MB. The substrate 12 is formed with two notches 16 at its two sides, respectively. Thus, the substrate 12 may be secured by the locking device 14 secured in the notches 16 so that the memory module can be secured.
Since the size of the substrate 12 is limited by the specification of the locking device 14, all substrate 12 have a length of 67.6 mm and a width of 31.75 mm. If the dynamic random access memory is packaged by a conventional TSOP (thin small outline package), the volume of the package is relatively large. Thus, it is impossible to arrange plural dynamic random access memories on the substrate 12 and to produce a memory module having a high capacity.
Moreover, please refer to FIG. 2. If the memory is packaged by way of a chip scale package (CSP), a package having a smaller size can be obtained. However, if eight memories are intended to be arranged on the substrate 12 to constitute a memory module having a capacity of 512 MB, the memory module occupies most space of the substrate 12. Thus, it is not so easy to layout the wires on the substrate 12 and to prevent the memories 10 from contacting the notches 16. In this case, the engagement between the locking device 14 and the notches 16 is adversely influenced.
In view of the above-mentioned problems, it is therefore an object of the present inventor to provide a memory module structure capable of efficiently arranging plural packaged memories on the substrate 12 having a certain size without adversely influencing the wire layout on the substrate 12. Thus, the capacity of the memory module can be increased.
It is a primary object of the invention to provide a memory module structure capable of arranging plural memories on the substrate to increase the capacity of the memory module.
To achieve the above-mentioned objects, the invention is characterized in that a memory module structure is used for being assembled on a locking device. The memory module includes a substrate and a plurality of memories. The substrate has certain long sides and short sides. Notches are formed on the short sides so that the substrate can be secured by the locking device. Each of the plurality of memories has a suitable length and width. Some memories of the plurality of memories are transversely mounted on the substrate with respect to the substrate. The other memories of the plurality of memories are longitudinally mounted on the substrate with respect to the substrate. According to this structure, it is possible to suitably arrange a plurality of memories on the substrate so as to increase the memory capacity of the memory module without adversely influencing the wire layout on the substrate.